CCTV in Britain is not all its cracked up to be, on the negative and the positive side. Even if the operator was competent, and there was coverage of the area, I doubt in a conflict with a police officer that you'd get much out of it, most of the time, you'd need the sound, and higher quality footage, to get much of a sense of the situation.
However, in practice different operators will have different standards, which makes it more complicated:
https://www.theguardian.com/cities/2015/sep/22/cctv-cameras-...
CCTV in Britain is not all its cracked up to be, on the negative and the positive side. Even if the operator was competent, and there was coverage of the area, I doubt in a conflict with a police officer that you'd get much out of it, most of the time, you'd need the sound, and higher quality footage, to get much of a sense of the situation.